Start from the promise shoppers meet
Every ad, email, and post makes a promise. Write that promise down before you touch the landing page, then check whether the page a shopper lands on actually keeps it. When the promise and the page disagree, people leave, and the campaign pays for a visit that never had a chance.
Send every click somewhere specific
A homepage is a hallway. A page built for the campaign is a room with one door out. Point each campaign at a page that continues its story, shows the product at the price advertised, and asks for the one action the campaign promised.
Answer the objections the click implies
A click is a question. Shoppers who click a free shipping ad want to see shipping before checkout. Shoppers who click a bundle ad want to see the bundle. Write down the question behind your best performing click and answer it on the first screen.
Review the campaign against the page
Track the campaign, its landing page, and the actions taken there as one unit. When results disappoint, ask first whether the page kept the promise before blaming the audience. Small alignment fixes often move the whole number.
Your next step: follow one campaign end to end.
Open your best campaign, click the ad, and read the page as a stranger would. Note every place the promise bends. Fix the first one and run the click again.